Fibrous structures, even textured and/or embossed fibrous structures, comprising a plurality of filaments and solid additives, for example fibers, are known in the art. However, such known fibrous structures do not comprise two or more regions that comprise different average weight % levels of solid additives. Such a known fibrous structure comprising a plurality of filaments and solid additives, for example fibers, such as pulp fibers, with a texture imparted thereto by embossing, does not comprise two or more regions that comprise different average weight % levels of solid additives. In other words, the known fibrous structures comprise a uniform level of solid additives throughout the fibrous structure, for example in the x-y plane of the fibrous structure (there are regions that comprise different average weight % levels of solid additives, for example fibers, such as pulp fibers).
Prior Art FIG. 1 shows an example of a known method 100 for making such a known fibrous structure. This known method 100 fails to create a fibrous structure 10 comprising two or more regions having different average weight % levels of solid additives. As shown in Prior Art FIG. 1, the method 100 comprises the step of mixing a plurality of filaments 12 with a plurality of solid additives 14. In one example, the solid additives 14 are wood pulp fibers, such as SSK fibers and/or Eucalyptus fibers, and the filaments 12 are polypropylene filaments. The solid additives 14 may be combined with the filaments 12, such as by being delivered to a stream of filaments 12 from a hammermill 66 via a solid additive spreader 67 to form a mixture of filaments 12 and solid additives 14. The filaments 12 may be created by meltblowing from a meltblow die 68. The mixture of solid additives 14 and filaments 12 are collected on a collection device, such as a belt 70 to form a fibrous structure 10. A forming vacuum 17 aids in the collection of the solid additives 14 and filaments 12 onto the collection device, by pulling air through the collection device. The amount of vacuum from the forming vacuum 17 was sufficient to collect the solid additives 14 an filaments 12 onto the collection device, but not great enough to result in redistribution of the solid additives 14 to create two or more regions within the fibrous structure 10 that exhibit different average weight % levels of solid additives 14. The resulting fibrous structure 10 may be passed through an embossing roll nip 69 to yield a finished, textured fibrous structure 10.
Fibrous structures made by the method described by Prior Art FIG. 1 have uniform distribution of solid additives which therefore renders the fibrous structure restricted to deliver overall performance and regional performance characteristically associated with the web possessing such overall composition of the solid additive. Consider how solid additives may generally dilute the generation of web properties such as strength, burst, flexibility, and visual aesthetics. Fibrous structures compromising solid additives may have enhanced strength, burst, flexibility, absorbency, and/or visual aesthetics if there was segregation of the solid additives into regions of the fibrous structure where they would accumulate and then provide for a separate region where the filament components could be consolidated to provide for a combined, superior, overall level of strength, burst, flexibility, and visual aesthetics. The overall performance of the fibrous structure may be maximized by having regions within the structure which are responsible for delivering one performance requirement such as strength, while a separate region delivers a separate performance requirement such as visual aesthetics. The delivery of overall fibrous structure performance within a region is directly related to the intensive properties imparted to the regions with the intensive properties comprising composition, thickness, basis weight, density, and combinations thereof.
Importantly, if the solid additives are reduced in level in one region, this region may become increased in concentration of filament components. The first region with increased filament concentration may be consolidated to achieve higher densities, high bond density, and higher individual bond strengths. With this type of structure, the solid additive level in a second region would be increased and as a result may deliver higher performance levels associated with the solid additive, such as thickness, absorbency, visual aesthetics, etc. in the second region. The overall performance of a fibrous structure combining these two regions may be superior to one where the solid additive level is uniformly distributed.
Therefore, a problem that has not been addressed by known fibrous structures comprising a plurality of filaments and a plurality of solid additive, such as fibers, is the creation of fibrous structures that comprise two or more regions comprising different average weight % levels of solid additives.
In light of the foregoing, there is a need for a fibrous structure that comprises two or more regions comprising different average weight % levels of solid additives that overcome the negatives of the known fibrous structures without such regions and methods for making such fibrous structures.